Fix imports for DRF 3.10 (#408)

Fixes #410
Fixes #411

requirements/testproj.txt

@@ -3,7 +3,9 @@ Pillow>=4.3.0
 django-cors-headers>=2.1.0
 django-filter>=1.1.0,<2.0; python_version == "2.7"
 django-filter>=1.1.0; python_version >= "3.5"
-djangorestframework-camel-case>=0.2.0
+#djangorestframework-camel-case>=0.2.0
+# tempory replacement of broken lib
+-e git+https://github.com/tfranzel/djangorestframework-camel-case.git@bd556d38fa7382acadfe91d93d92d99c663248a9#egg=djangorestframework_camel_case
 djangorestframework-recursive>=0.1.2
 dj-database-url>=0.4.2
 user_agents>=1.1.0

src/drf_yasg/generators.py

@@ -4,14 +4,23 @@
 from collections import OrderedDict, defaultdict
 
 import uritemplate
+import rest_framework
 from coreapi.compat import urlparse
 from rest_framework import versioning
 from rest_framework.compat import URLPattern, URLResolver, get_original_route
 from rest_framework.schemas.generators import EndpointEnumerator as _EndpointEnumerator
-from rest_framework.schemas.generators import SchemaGenerator, endpoint_ordering, get_pk_name
-from rest_framework.schemas.inspectors import get_pk_description
+from rest_framework.schemas.generators import endpoint_ordering, get_pk_name
+
 from rest_framework.settings import api_settings
 
+from packaging.version import Version
+if Version(rest_framework.__version__) < Version('3.10'):
+    from rest_framework.schemas.generators import SchemaGenerator
+    from rest_framework.schemas.inspectors import get_pk_description
+else:
+    from rest_framework.schemas import SchemaGenerator
+    from rest_framework.schemas.utils import get_pk_description
+
 from . import openapi
 from .app_settings import swagger_settings
 from .errors import SwaggerGenerationError

testproj/snippets/serializers.py

@@ -1,8 +1,13 @@
+import rest_framework
 from decimal import Decimal
 
 from django.contrib.auth import get_user_model
+from packaging.version import Version
+if Version(rest_framework.__version__) < Version('3.10'):
+    from rest_framework.compat import MaxLengthValidator, MinValueValidator
+else:
+    from django.core.validators import MaxLengthValidator, MinValueValidator
 from rest_framework import serializers
-from rest_framework.compat import MaxLengthValidator, MinValueValidator
 
 from snippets.models import LANGUAGE_CHOICES, STYLE_CHOICES, Snippet, SnippetViewer
 

tox.ini

@@ -9,6 +9,7 @@ envlist =
     py27-django111-drf{38,39},
     py{35,36}-django{111,21,22}-drf{38,39},
     py37-django{21,22}-drf{38,39},
+    py37-django{21,22}-drf310,
     djmaster, lint, docs
 
 [testenv:.package]
@@ -23,6 +24,7 @@ deps =
 
     drf38: djangorestframework>=3.8,<3.9
     drf39: djangorestframework>=3.9,<3.10
+    drf310: djangorestframework>=3.10
 
     typing: typing>=3.6.6